You seem to be conflating MIDI and DIN Sync yet again. The clock signal on pin 3 of the DIN connector is only used/relevant to DIN Sync. It has absolutely no relevance to MIDI, The 7th Guest, or any other game. You'd asked a number of similar questions a few years ago; I recommend going back and reviewing those responses.

My gibberish is going over the history of those TI for Tandy type ASICS. It's an investigation for who is responsible for defining the standards for PC audio.

For MIDI, IIRC it's called the "go back signal" or something like that on 7th Guest. The whole intelligent mode discussion convinced me there's some sort of handshake or a feedback signal. I don't recall what they call it, but it would be on the LAPC-I setting of the game, not the sound canvas. Only the Edirol cm-32l, AFAIK, ever responded to it.

Texas Instruments SN76489AN which was used on the Sega SG-1000 game console. It has one feature missing - it does not automatically switch between analog and s/pdif output.

Why would a simple 3-voice PSG have S/PDIF output?

It is an incidental fix from modifying the chip to handle "PC speaker" mode.

An incidential fix? What does a SN76489AN have to do with PC speaker "mode"?

What OS did it use?

The SN76489 uses no OS. It has no CPU, so it cannot run an OS.

Was it Dr-DOS 6.28?

There is no DR-DOS version 6.28.

I think there was a SN76489ANBA ASIC that was Edirol branded that also handled system error messages.

There never was any "SN76489ANBA" with those four letters at the back, and Edirol never had anything to do with SN76489 chips.

Only the Edirol cm-32l

And there never was an Edirol CM-32L either. Roland's Edirol subsidiary was founded in 1994, long after the CM-32L was discontinued. And the CM-32L never used CQM synthesis, either, nor was it ever compatible to it.

In other news, the name on the synthesizer ASIC on the original Gameblaster card is "soundblaster."

What the hell?

And the current post:

Does any game besides Seventh Guest look for a CLK signal on pin 3 of the MIDI input?

No game reads the MIDI "Input". Why would it? And, as pointed out, there is no CLK signal on MIDI In anyway, so no game can use it.

Every single sentence of his is just utter nonsense. It's just connecting thoughts together that have nothing to do with each other. Nothing makes any sense. I still believe it's a bot.

I hear if you play this game in LAPC-I mode with the Edirol CM-32l, a MIDI version of Hallowed be thy Name will play, scaring the hell out of you. I think the dog takes the place of the singer, if heard correctly.

Maybe SB 16 2.0 did and some game used it and that's what people are clamoring about the card.

I think you are confusing that with the Front Fareast Sound Doctor DX. Did you know that most of the later Sound Blaster 16 Pro Galaxy cards (CT1138 and up) are actually rebranded FFE SD-DXs? It's true. Of course, the SD-DX itself is just a clone of the Kasheng (卡聖) NT-666, and given that Kasheng took over Gouder Industry (哥德) when they went bankrupt, some earlier products with the same ASIC may also exist.

I hear if you play this game in LAPC-I mode with the Edirol CM-32l, a MIDI version of Hallowed be thy Name will play, scaring the hell out of you. I think the dog takes the place of the singer, if heard correctly.

How exciting! I have also heard that when you connect an IBM Music Feature card to the SN76489's MIDI out port, then the original uncensored version of Tetris by Spectrum Holobyte (the one with the airplane on the title screen) will show a nuclear explosion and use the OPP chip to play Johann Sebastian Bach's Ride of the Valkyries. Not many people know that.

I am making a mistake here, there is a separate cm-32l mode for 7th Guest. In this mode, with the Edirol cm-32l you will here a wolf howling rather than a dog barking. I'd like to try it on the Lord of the Rings as well, upon which I used a Roland branded cm-32l.